Dicalcium Phosphate Anhydrous: An Appropriate Bioceramic in Regeneration of Critical-Sized Radial Bone Defects in Rats.

The present study aimed to evaluate and compare the effectiveness of composites of calcium phosphates including β-tri calcium phosphate (β-TCP), dicalcium phosphate anhydrous (DCPA, monetite), mono-calcium phosphate monohydrate (MCPM), and hydroxyapatite (HA) with the chitosan-gelatin-platelet gel (CGP) on the healing of experimentally induced critical size radial bone defects in rats after 8 weeks of injury. Eighty bilateral bone defects were created in the radial bones of 40 adult male Sprague-Dawley rats. The defects were either left empty (untreated or defect group), or treated with autograft, CGP, CGP-DCP, CGP-TCP, CGP/β-TCP/DCPA (CGP-TD), CGP-TD/MCPM (CGP-TDM), and CGP-TDM/HA (CGP-TDMH) scaffolds. The injured forelimbs were evaluated by radiography, gross morphology, three-dimensional computed tomography scanning, histopathology, histomorphometry, scanning electron microscopy, and biomechanical testing. The materials were analyzed using X-ray diffraction to verify the crystalline nature of their structures, and their crystallinity was revealed based on the diffraction peaks achieved from the XRD analysis. The best results were achieved by the CGP-DCP scaffold and the autograft. The CGP-TCP and CGP-TDMH scaffolds were not degraded, while the CGP-DCP, CGP-TDM, CGP-TD, and CGP scaffolds were biodegraded and enhanced bone formation compared with the CGP-TCP and CGP-TDMH groups (P < 0.05). Overall, the CGP-DCP treated defects showed significant improvement in bone formation and union, bone volume, maximum load, and stiffness compared to the CGP group (P < 0.05). It could be concluded that the CGP-DCP scaffold can be considered as a suitable substitute to autograft. In fact, this study demonstrated that DCPA or monetite has high healing potential due to its biocompatibility, biodegradability and biomechanical, osteoconductive and osteoinductive properties of this bioceramic.